You cannot use Jumbo Frames on a Broadcom card that is configured as a hardware initiator performing iSCSI Offload functions. You can either use Jumbo Frames or iSCSI Offload and you cannot use both together with the Broadcom adapters.

Jumbo Frames in ESXi 5.1 and later

Jumbo frames for all iSCSI adapters in vSphere 5.1 and vSphere 5.5 can be configured using the user interface (UI). This applies to Software iSCSI, Dependent Hardware iSCSI and Independent Hardware iSCSI adapters.

To enable Jumbo Frames for software and dependent hardware iSCSI adapters in the vSphere Web Client, change the default value of the MTU parameter:

Browse to the host in the vSphere Web Client navigator.

Click the Manage tab.

Click Networking.

Click Virtual Switches, and select the vSphere switch that you want to modify from the list.

Click Edit Settings.

On the Properties page, change the MTU parameter.

Note: This step sets the MTU for all physical NICs on that standard switch. The MTU value should be set to the largest MTU size among all NICs connected to the standard switch.

To enable Jumbo Frames for independent hardware iSCSI adapters in the vSphere Web Client, change the default value of the MTU parameter:

Use the Advanced Options settings to change the MTU parameter for the iSCSI HBA.

Browse to the host in the vSphere Web Client navigator.

Click the Manage tab.

Click Storage.

Click Storage Adapters, and select the independent hardware iSCSI adapter from the list of adapters.

Under Adapter Details, click the Advanced Options tab.

Click Edit.

Change the value of the MTU parameter.

Jumbo Frame 5.0 and earlier

To set Jumbo Frames on vSwitch:

Log in to the ESXi/ESX host console directly.

To set the MTU size for the vSwitch:

Run this command for ESX 3.5 and ESXi/ESX 4.x:

# esxcfg-vswitch -m MTUvSwitch#

Example:

# esxcfg-vswitch -m 9000 vSwitch2

Run this command for ESXi 5.0:

# esxcli network vswitch standard set -m MTU -v vSwitch#

Example:

# esxcli network vswitch standard set -m 9000 -v vSwitch2

Note: This command sets the MTU for all uplinks on that vSwitch. Set the MTU size to the largest MTU size among all the virtual network adapters connected to the vSwitch.

To display a list of vSwitches on the host, and to check that the configuration of the vSwitch is correct:

Run this command for ESX 3.5 and ESXi/ESX 4.x:

# esxcfg-vswitch -l

Run this command for ESXi 5.0:

# esxcli network vswitch standard list

Configuring Jumbo Frames on a vSphere Standard Switch

To configure Jumbo Frames on a vSphere Standard Switch:

Log into the vSphere Client.

Select the Hosts and Clusters inventory view.

Under the host Configuration tab, click Networking.

Click Properties for the vSphere standard switch associated with the VMkernel to modify.

To create a Jumbo Frames-enabled VMkernel interface on a vNetwork Standard Switch:

Log directly into the ESX host console.

Obtain the current vSwitch and portgroup configuration with the esxcfg-vswitchcommand:

# esxcfg-vswitch -l

To create a VMkernel interface with Jumbo Frames support, you must first create a portgroup on an existing vSwitch:

# esxcfg-vswitch -A vmkernel_port_group_namevSwitch#

Example:

# esxcfg-vswitch -A iSCSI vSwitch2

Note: If you plan to have a vSwitch that contains only the iSCSI port group, you can specify the MTU for the vSwitch to be 9000 and must specify an MTU of 9000 when creating the VMkernel port as well in the next step. To configure a vSwitch to use Jumbo Frames (MTU 9000):

# esxcfg-vswitch -m 9000 vSwitch#

Example:

# esxcfg-vswitch -m 9000 vSwitch2

To create a VMkernel connection with Jumbo Frame support:

Run this command for ESX 3.5 and ESXi/ESX 4.x:

# esxcfg-vmknic -a -i ip_address -n netmask -m MTU portgroup_name

Example:

# esxcfg-vmknic -a -i 192.168.1.5 -n 255.255.252.0 -m 9000 iSCSI

Note: If the vmnic port is already created, use the command for ESXi/ESX 4.1 only:

# esxcfg-vmknic -m 9000 portgroup_name

Example:

# esxcfg-vmknic -m 9000 iSCSI

Run this command for ESXi 5.x:

# esxcli network ip interface set -m 9000 -i vmk_interface

Example:

# esxcli network ip interface set -m 9000 -i vmk1

To display a list of VMkernel interfaces, and to check that the configuration of the Jumbo Frame‐enabled interface is correct: